In the “old days” in the clinical laboratory, the main sources of potential radioactive substances were found in the Radioimmunoassay (RIA) department. Techs who worked in this specialized testing area handled reagents which often were radioactive isotopes. The materials were used to label specific antigens which would compete with unlabeled antigen from patient samples. This method would allow the determination of high-quality quantitative diagnostic values. In the early 1990s, radio-immunoassays were commonly used to perform thyroid testing, narcotics assays, and a variety of hormone level analyses. Unfortunately, the use of such isotopes for testing was costly, difficult to automate, and their use was potentially hazardous to staff. Eventually this major testing method was replaced by ELISA testing, chemiluminescence, and other techniques, but some labs still do utilize RIA analysis today.
In the Anatomical Pathology areas, there has been potential radiation exposure from certain specimens in the past, and newer techniques have introduced other sources into the lab as well. Tissues (such as thyroid gland sections) are not typically removed from patients when treated with radioactive dyes, but it can occur. Good communication to the lab from surgery staff is important so that no one is unnecessarily exposed. Sentinel lymph node biopsies are sometimes infused with radioactive tracer dyes. Pathology staff may also receive radioactive seeds used to treat prostate cancer. Usually these seeds have decayed sufficiently and are inert, but that may not always be true. Again, clear communication about these samples is important. Other radioactive seeds are now used for breast tumor localization, and these do arrive in the lab while radioactive, and they must be handled and stored with care.
The best protection from radiation exposure is distance, duration, and barriers. Being away from a radiation sources isn’t always possible, but working with them for short periods and using some form of barrier protection will help. The types of radioactive material handled in labs today generally emit low levels of energy, and the use of Standard Precautions offers sufficient protection. Gloves, lab coats and face protection will provide the necessary protective barriers when handling these standard materials (Note: items like thyroid tissue that have been infused with Iodine-125 contain above-normal levels of energy and should be treated with extra care).
The College of American Pathologists (CAP) updated its regulations last year regarding radiation safety in the laboratory. Some of the standards were moved from the Anatomic Pathology checklist, and some are new. When asked, the CAP has stated that these standards do not apply to laboratories that handle low-level radiation samples such as sentinel lymph node biopsies.
First, the regulations require radiation safety handling policies and procedures which are maintained in a radiation safety manual. This manual can be paper or electronic, and it does not need to be separate from other lab safety policies. The policies should need to spell out who in the lab is authorized and restricted from handling radionuclides. Specific procedures should also be maintained to describe what actions to follow in the event of a radionuclide leak or damage to radioactive seeds. All radioactive materials and supplies should be inspected to ensure that there is no leakage or compromise that could expose staff unnecessarily.
The updated standards also require workplace radiation decontamination procedures, and labs that perform this type of work must keep records that document the effectiveness of the decontamination processes. Laboratories that handle radioactive substances must post radiation warning signs to communicate to others the potential dangers present, and all laboratory and medical staff must have comprehensive training prior to handling radioactive substances. Lastly, the CAP checklist now requires that if radioactive substances are handled in the lab, a laboratory representative must participate as a member of an institutional radiation safety committee.
Many things have changed in the laboratory setting over the past decades, and the regulations keep changing in an effort to stay current. The bottom line for radiation safety regulations in the lab is that staff need to be aware of what radioactive substances they may become exposed to, so they need to know safe handling processes as well as emergency response procedures. In the real world of lab medicine, radioactive substances do not glow, so lab staff may not be aware of the dangers when they enter the department. If the proper communication and practices are in place, however, everyone can maintain the minimum radiation exposure levels needed to live long and safe lives.
–Dan Scungio, MT(ASCP), SLS, CQA (ASQ) has over 25 years experience as a certified medical technologist. Today he is the Laboratory Safety Officer for Sentara Healthcare, a system of seven hospitals and over 20 laboratories and draw sites in the Tidewater area of Virginia. He is also known as Dan the Lab Safety Man, a lab safety consultant, educator, and trainer.